E-cadherin expression correlates with histologic type but not tumour grade in invasive breast cancer.

ABSTRACT

The traditional classification of infiltrating breast carcinomas into ductal and lobular can be diagnostically challenging in a small proportion of cases with equivocal histological features and in in-situ lesions with overlapping features. Distinguishing between the infiltrating ductal (IDC) and lobular (ILC) carcinomas is clinically important because of the different pattern of systemic metastases and prognostic evaluation. E-cadherin is a potentially useful immunohistochemical marker which may serve to differentiate between the two tumour types. We therefore studied E-cadherin expression in 32 cases of breast carcinomas comprising 16 IDCs and 16 ILCs. The correlation between E-cadherin expression and the histological grade of IDCs was also analysed. Our results showed complete loss of E-cadherin expression in all ILCs, while the IDCs consistently showed variable E-cadherin positivity. No significant correlation was found between E- cadherin expression and the histological grade of IDCs. We conclude from this study that E-cadherin is a useful marker to differentiate between IDC and ILC of the breast. A larger study of IDCs is now needed to further evaluate the correlation between E-cadherin and tumour grade to estimate its prognostic potential.